5-4 Dimensions and Shape Standards for Automation-compatible (Unenveloped) Disc Carriers Each unenveloped disc carrier must meet the basic standards for a machinable letter in DMM 201.1.0 and have the following characteristics. Length: Not more than 9.75" or less than 7.25". Height: Not more than 6" or less than 5.5". Thickness: Not more than 0.25" or less than 0.009". Weight: Not more than 3 ounces. Paper basis weight: Minimum 75-pound book-grade paper or equivalent. The paper stock must meet the industry standard. The stock must be free from groundwood unless it is coated with a substance adding to the stock’s ability to resist an applied bending force. Folds or perforations: Must be parallel to the address. Tabs: Must meet the requirements for pieces prepared with folds or perforations parallel to the address.